What? People actually leave the airport on a same day turn?
If you don't have enough time to run into the city and prefer to hang out at the airport, then my favorites for ease and as little hassle as possible, plus amenities are:
International - Singapore, Amsterdam, Lima, Peru (an easy turn but not much amenities), Hong Kong, Tokyo Narita (not much ease since always crowded but great plane watching), and Munich.
Domestic - San Francisco, Seattle, Honolulu, Boston.